© C

opyr

ight

Inst

itut F

ranç

ais

de la

Vig

ne e

t du

Vin

- M

. Bou

vier

- ju

illet

201

4

P. COTTEREAU - Institut Français de la Vigne et du Vin, FranceF. TROTTA - Département de chimie, Université de Turin (UNITO), ItalieR. LOPEZ - Laboratorio de análisis del aroma y enología, Universidad de Zaragoza, Espagne

Protein stabilization is an important phase of winemaking, particularly for wines exported and sold through organized distribution. Presently, stabilization is obtained through bentonite fining, an effective practice although having some side negative effect on wine quality and environment; for many decades the European wine producers have looked for alternatives.The research activity performed within the European project STABIWINE (FP7, GA n. 314903, www.stabiwine.eu) is aimed to identify a biopolymer effective for protein removal, without negative effects on wine quality, composed exclusively by harmless and natural components, and with production costs compatible with wine industry standards.Different oligosaccharides starch derivatives are used, namely cyclodextrins sometimes in combination with linear oligosaccharides.

MATERIALS AND METHODS

USING RETICULATED BIOPOLYMERS FOR PROTEIN STABILIZATION OF WINE

Around forty reticulated biopolymers (RBP) were studied during the first 18 months of the project. They were synthesized and characterized by University of Turin. Depending on favorable physicochemical characteristics (particle size, infrared spectra, zeta potentials ...) selected polymers were tested on unstable wine. Lab stabilization estimation has been done by IFV (Heat tests, SDS-PAGE electrophoresis). Volatile compounds have been analyzed by the University of Zaragoza (GC-FID and GC-MS).

CONCLUSIONS

The collaboration between IFV and UNITO has allowed to identify 2 or 3 polymers with efficiency on protein stabilization equivalent to a high-performance sodium bentonite. First sensory observations and aromatic compounds analysis (produced by the University of Zaragoza), show no negative impact on the flavors of the treated wines.

Figure 1. example of tested RBP - Citric acid

Figure 2. Relation between heat test and eliminated proteins percentage (by analysis) – 2 different RBP with a good efficacy compared to bentonite / Cyc A is derived from ß-cyclodextrins and Line A is an association of ß-cyclodextrins and linear polysaccharide

+

citric acid

heat

inorganic salts, water

Figure 3. Impact of treatment on the aromatic composition of wines for 4 compounds (UNIZAR analysis) - No significant difference compared to control wines

The research leading to these results has received funding from the European Union's Seventh Framework Programme managed by REA Research Executive Agency http://ec.europa.eu/research/rea (FP7/2007-2013) under grant agreement n°314903